// stylelint-disable selector-no-qualifying-type
// Make the div behave like a button
.btn-group,
.btn-group-vertical {
    position: relative;
    display: inline-flex; //得包裹btn，所以不能是block的样子
    vertical-align: middle; // match .btn alignment given font-size hack above
    >.btn {
        position: relative;
        flex: 1 1 auto; //自动增长，自动压缩，宽度自动
        // Bring the hover, focused, and "active" buttons to the front to overlay
        // the borders properly
        @include hover {
            z-index: 1;
        }
        &:focus,
        &:active,
        &.active {
            z-index: 1;
        }
    }
}

// Optional: Group multiple button groups together for a toolbar
.btn-toolbar {
    display: flex; //toolbar需要是100%宽度的
    flex-wrap: wrap;
    justify-content: flex-start;
    .input-group {
        width: auto;
    }
}

.btn-group {
    // Prevent double borders when buttons are next to each other
    >.btn:not(:first-child),
    >.btn-group:not(:first-child) {
        margin-left: -$btn-border-width;
    }
    // Reset rounded corners
    >.btn:not(:last-child):not(.dropdown-toggle),
    >.btn-group:not(:last-child)>.btn {
        @include border-right-radius(0);
    }
    >.btn:not(:first-child),
    >.btn-group:not(:first-child)>.btn {
        @include border-left-radius(0);
    }
}

// Sizing
//
// Remix the default button sizing classes into new ones for easier manipulation.
.btn-group-sm>.btn {
    @extend .btn-sm;
}

.btn-group-lg>.btn {
    @extend .btn-lg;
}

//
// Split button dropdowns
//
.dropdown-toggle-split {
    padding-right: $btn-padding-x * .75;
    padding-left: $btn-padding-x * .75;
    &::after,
    .dropup &::after,
    .dropright &::after {
        margin-left: 0;
    }
    .dropleft &::before {
        margin-right: 0;
    }
}

.btn-sm+.dropdown-toggle-split {
    padding-right: $btn-padding-x-sm * .75;
    padding-left: $btn-padding-x-sm * .75;
}

.btn-lg+.dropdown-toggle-split {
    padding-right: $btn-padding-x-lg * .75;
    padding-left: $btn-padding-x-lg * .75;
}

// The clickable button for toggling the menu
// Set the same inset shadow as the :active state
.btn-group.show .dropdown-toggle {
    @include box-shadow($btn-active-box-shadow);
    // Show no shadow for `.btn-link` since it has no other button styles.
    &.btn-link {
        @include box-shadow(none);
    }
}

//
// Vertical button groups
//
.btn-group-vertical {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    >.btn,
    >.btn-group {
        width: 100%;
    }
    >.btn:not(:first-child),
    >.btn-group:not(:first-child) {
        margin-top: -$btn-border-width;
    }
    // Reset rounded corners
    >.btn:not(:last-child):not(.dropdown-toggle),
    >.btn-group:not(:last-child)>.btn {
        @include border-bottom-radius(0);
    }
    >.btn:not(:first-child),
    >.btn-group:not(:first-child)>.btn {
        @include border-top-radius(0);
    }
}

// Checkbox and radio options
//
// In order to support the browser's form validation feedback, powered by the
// `required` attribute, we have to "hide" the inputs via `clip`. We cannot use
// `display: none;` or `visibility: hidden;` as that also hides the popover.
// Simply visually hiding the inputs via `opacity` would leave them clickable in
// certain cases which is prevented by using `clip` and `pointer-events`.
// This way, we ensure a DOM element is visible to position the popover from.
//
// See https://github.com/twbs/bootstrap/pull/12794 and
// https://github.com/twbs/bootstrap/pull/14559 for more information.
.btn-group-toggle {
    >.btn,
    >.btn-group>.btn {
        margin-bottom: 0; // Override default `<label>` value
        input[type="radio"],
        input[type="checkbox"] {
            position: absolute;
            clip: rect(0, 0, 0, 0);
            pointer-events: none;
        }
    }
}